source: Dev/branches/rest-dojo-ui/server/classes/models/SessionInstance.php @ 263

<?php
// Survey database interface class as intermediate for storing data from the site to the RDF database 
require_once 'rdfConstants.php';
// Include RAP Library to write RDF files
include(RDFAPI_INCLUDE_DIR . "RDFAPI.php");

/**
 * Description of SessionInstance
 *
 * @author jkraaijeveld
 */

class SessionInstance extends ResearchToolObject
{
        public static $filename = 'data/sessions/sessioninstances.rdf';

        public $title;
        public $location;
        public $facilitator;
        public $starttime;
        public $endtime;
        public $notes;
        public $session;
        public $resultset;

        /**
         * Constructor for a SessionInstance object
         * @param type $uid
         * @param type $title
         * @param type $location
         * @param type $facilitator
         * @param type $starttime
         * @param type $endtime
         * @param type $notes
         * @param type $session
         * @param type $resultset
         */
        public function __construct($uid = null, $title = null, $location = null, $facilitator = null, $starttime = null, $endtime = null, $notes = null, $session = null, $resultset = null)
        {
                if(!isset($uid))
                {
                        $uid = md5(uniqid(rand(), true));
                }
                $this->uid = $uid;
                $this->title = $title;
                $this->location = $location;
                $this->facilitator = $facilitator;
                $this->starttime = $starttime;
                $this->endtime = $endtime;
                $this->notes = $notes;
                $this->session = $session;
                $this->resultset = $resultset;
        }

        /*
         * function evaluate()
         * Evaluates all the references of this object.
         */
        public function evaluate()
        {
                if(is_string($this->facilitator))
                {
                        $result = User::get(array("uid" => $this->facilitator));
                        if(!isset($result[0]))
                                return false;
                        $this->facilitator = $result[0];
                }

                if(is_string($this->session))
                {
                        $result = Session::get(array("uid" => $this->session));
                        if(!isset($result[0]))
                                return false;
                        $this->session = $result[0]; 
                }

                if(is_string($this->resultset))
                {
                        $result = ResultSet::get(array("uid" => $this->resultset));
                        if(!isset($result[0]))
                                return false;
                        $this->resultset = $result[0];
                }
                return true;
        }

        /**
         * function save()
         * Saves the current object into the database.
         */
        public function save()
        {
                //If evaluation fails, some references are incorrect.
                //We shouldn't save in this case. Instead - let the user know. This function returns false if the evaluation has failed.
                //TODO: Decide how to fix invalid references graciously.
                if(!$this->evaluate()) 
                        throw new Exception('Evaluation failed.');

                //Ensure the required folder exists.
                if(!is_dir('data/sessions/'))
                        mkdir('data/sessions/');

                $model = ResearchToolObject::load(SessionInstance::$filename);

                $resourceSInstance = new Resource(SESSIONINSTANCE . '/' . $this->uid);
                //Remove the old value stored with the given id
                $model->subtract($model->find($resourceSInstance, null, null));

                //Set the new values
                $resourceSInstanceType = new Resource(SESSIONINSTANCE);
                $predicateType = new Resource(RTYPE);
                $model->add(new Statement($resourceSInstance, $predicateType, $resourceSInstanceType));

                $sInstanceId = new Literal($this->uid);
                $predicateId = new Resource(UID);
                $model->add(new Statement($resourceSInstance, $predicateId, $sInstanceId));

                $sInstanceTitle = new Literal($this->title);
                $predicateTitle = new Resource(TITLE);
                $model->add(new Statement($resourceSInstance, $predicateTitle, $sInstanceTitle));

                $sInstanceLocation = new Literal($this->location);
                $predicateLocation = new Resource(LOCATION);
                $model->add(new Statement($resourceSInstance, $predicateLocation, $sInstanceLocation));

                $sInstanceFacilitator = new Literal($this->facilitator->uid);
                $predicateFacilitator = new Resource(FACILITATOR);
                $model->add(new Statement($resourceSInstance, $predicateFacilitator, $sInstanceFacilitator));

                $sInstanceStartTime = new Literal($this->starttime->getTimestamp());
                $predicateStartTime = new Resource(STARTTIME);
                $model->add(new Statement($resourceSInstance, $predicateStartTime, $sInstanceStartTime));

                $sInstanceEndTime = new Literal($this->endtime->getTimestamp());
                $predicateEndTime = new Resource(ENDTIME);
                $model->add(new Statement($resourceSInstance, $predicateEndTime, $sInstanceEndTime));

                if(isset($this->notes))
                {
                        foreach($this->notes as $note)
                        {
                                $sInstanceNote = new Literal($note);
                                $predicateNote = new Resource(HAS_NOTE);
                                $model->add(new Statement($resourceSInstance, $predicateNote, $sInstanceNote));
                        }
                }

                $sInstanceSession = new Literal($this->session->uid);
                $predicateSession = new Resource(OF_SESSION);
                $model->add(new Statement($resourceSInstance, $predicateSession, $sInstanceSession));

                if(isset($this->resultset))
                {
                        //$sInstanceResultSet = new Literal($this->resultset->uid);
                        $sInstanceResultSet = new Literal($this->resultset);
                        $predicateResultSet = new Resource(HAS_RESULTSET);
                        $model->add(new Statement($resourceSInstance, $predicateResultSet, $sInstanceResultSet));
                }
                $model->saveAs(SessionInstance::$filename, 'rdf');
                return true;
        }

        /**
         * function get()
         * @param type $arguments : An array containing one or more of the following elements:
         * 'uid', 'title', 'location', 'facilitator', 'starttime', 'endtime' 'notes', 'session', 'resultset'
         */
        public static function get($arguments)
        {
                $model = ResearchToolObject::load(SessionInstance::$filename);

                //Build the query string
                $querystring = '
                        PREFIX predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
                        PREFIX resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
                        SELECT DISTINCT ?uid, ?title, ?location, ?facilitator, ?starttime, ?endtime, ?of_session, ?has_resultset 
                        WHERE
                        {
                                _sessioninstance predicates:resource_type resources:sessioninstance ;
                                predicates:uid ?uid ;
                                predicates:title ?title ;
                                predicates:location ?location ;
                                predicates:facilitator ?facilitator ;
                                predicates:starttime ?starttime ;
                                predicates:endtime ?endtime ;
                                predicates:of_session ?of_session ;
                                predicates:has_resultset ?has_resultset ;
                                ' . ResearchToolObject::createArguments($arguments) . '
        }';
                //Query the model
                $results = $model->sparqlQuery($querystring);
                $sessioninstances = array();
                if(!empty($results))
                {       
                        foreach($results as $result)
                        {
                                //Create a SessionInstance object out of every result. Get all the required fields as well.
                                $notes = SessionInstance::getNotes($model, $result['?uid']->label);
                                $resultset = isset($result['?has_resultset']) ? $result['?has_resultset']->label : null;
                                $starttime = new DateTime();
                                $starttime->setTimestamp(intval($result['?starttime']->label));
                                $endtime = new DateTime();
                                $endtime->setTimestamp(intval($result['?endtime']->label));
                                $sessioninstances[] = new SessionInstance(  
                                        $result['?uid']->label,
                                        $result['?title']->label,
                                        $result['?location']->label,
                                        $result['?facilitator']->label,
                                        $starttime,
                                        $endtime,
                                        $notes,
                                        $result['?of_session'],
                                        $resultset
                                );
                        }
                }
                return $sessioninstances;
        }
        
        /**
         * function getNotes()
         * param type $uid : The SessionInstance uid for which the notes should be retrieved.
         */
        public static function getNotes($model, $uid)
        {
                $result = $model->findRegex("[(".$uid.")]", "[(has_note)]", null);
                $iterator = $result->getStatementIterator();
                $notes = array();
                while($iterator->hasNext())
                {
                        $element = $iterator->next();
                        $notes[] = $element->getLabelObject();
                }
                return $notes;
        }


}